Conventionally, a package-storage type engine generator is known, in which engine intake and exhaust system components are provided in an upper portion of a package (see, for example, Patent Document 1). The engine generator described in Patent Document 1 includes a device chamber in which are disposed an engine and a refrigerant device such as a compressor, a heat exchange chamber in which are disposed an outdoor heat exchanger and a fan, and a drain pan also used as an upper/lower partition wall partitioning the lower device chamber and the upper heat exchange chamber. A through hole, which communicates the device chamber with the heat exchange chamber, is formed in the drain pan that is also used as the upper/lower partition wall. A circumference of the through hole is covered with an external duct.